Cytauxzoon paradoxurus n. sp., a novel Cytauxzoon species identified in common palm civets in Singapore.

Abstract

Background: The common palm civet (Paradoxurus musangus) is a species native to Southeast Asia. Highly adapted to urbanised environments, these civets can often be found in proximity to humans and companion animals, raising the concern of pathogen transmission at the human-wildlife and wildlife-domestic animal interface. Whilst there have been reports of various bacteria and viruses detected in civets, little is known about the protozoa that they may harbour. In this study, we screened the common palm civets in Singapore for tick-borne protozoan parasites known as piroplasms.

Methods: Over a 2-year period, blood samples were opportunistically collected from 135 wild common palm civets following a physical examination. The sex and weight of each civet were recorded, and any ectoparasites detected were identified through DNA barcoding. DNA extracts of blood samples were screened using a PCR assay targeting the 18S rRNA gene of piroplasmids.

Results: A novel Cytauxzoon species was detected in 29 civets (21.5%), and a statistically significant association was found between infection and the civet's weight. Two cat flea (Ctenocephalides felis) specimens were discovered on two sampled civets; however, Cytauxzoon DNA was not detected in either the flea or the sampled civet. Phylogenetic analysis of the Cytauxzoon 18S rRNA gene sequences from 29 civets revealed that this piroplasmid is most closely related to a Cytauxzoon sp. detected in meerkats in South Africa but molecularly distinct from the six currently described Cytauxzoon species.

Conclusions: This detection documents the first molecular confirmation of Cytauxzoon sp. infection in Southeast Asia and the first report of Cytauxzoon sp. in a viverrid host. Further studies are required to determine the vector involved in the transmission of this novel Cytauxzoon species, as no ticks were found on the sampled civets. The discovery of Cytauxzoon paradoxurus n. sp. highlights the importance of expanded biosurveillance to better understand the diversity of piroplasms harboured by wildlife in the region and its potential for cross-species transmission.